Ghosts are a type of enemy that exists in the void. These huge enemies look like ghosts and they float in the air, so you'll need a ranged weapon to defeat them. Each ghost drops 0 to 2 gunpowder, and up to 5 gunpowder if your weapon is equipped with robbery enchant.

Crawlers have always been the most common method of finding gunpowder in Minecraft, although there are now better ways to collect it outside of combat. When a creeper is defeated, it drops 0 to 2 gunpowder, which you can increase to 5 with each level of plunder enchant.